Autonomous driving company Waymo alleged today in court that the formation of rival Otto was a ruse concocted between its founder Anthony Levandowski and eventual acquirer Uber to hide the fact that he immediately went to work for the ride-hailing company after leaving Waymo’s parent company, Google.

To prove its case, Waymo points to a stock grant with a vesting date of January 28, 2016 — the day after Levandowski resigned without notice — that grants Levandowski more than 5 million shares in Uber. The shares are estimated to be worth more than $250 million.

Uber and Waymo are facing off in court today in their ongoing lawsuit over trade secret and patent infringement, where Waymo is seeking an injunction against Uber that would stop it from using Waymo’s trade secrets in its self-driving car technology.

Waymo claims that a former engineer, Anthony Levandowski, stole 14,000 confidential files before leaving the company to start an autonomous truck company, Otto. Uber later acquired Otto in a deal worth about $680 million.

An Uber spokesperson said that the stock grant was issued around the time of the Otto acquisition in August 2016, and that it is common for vesting deals to back-date

to the formation of an acquired startup.

While Waymo says the date of the agreement shows that Uber planned to acquire Otto much earlier than originally disclosed, Uber says the actual date of the agreement was much later. This point will likely be a pivotal one in the case ahead.

Waymo also displayed emails in court today sent between Uber executives. The emails showed discussions about meeting with Levandowski and the formation of a new company, referred to as “NewCo.”

One email showed Brian McClendon, an executive who formerly worked on Google Maps before joining Uber, discussing a meeting with Levandowski about LiDAR that allegedly took place January 13, 2016. Waymo has previously alleged that Levandowski met with Uber execs before his departure from Google. Another email on which McClendon was cc’ed contained an attachment labeled “NewCo_Milestones_v5” and noted, “This list of deliverables is a high bar for sure. But then again so is what [Levandowski] is asking for in $$.” (McClendon resigned from Uber in March.)

Waymo also showed notes created by Scott Boehmke, a LiDAR expert Uber hired from Carnegie Mellon, that referenced “NewCo” as early as October 2015.

Despite this new evidence, Judge William Alsup appeared skeptical that Waymo could prove Uber is using its trade secrets and justify a preliminary injunction. “You didn’t sue [Levandowski], you sued Uber,” Alsup said. “What if it turns out that Uber is totally innocent? Let’s say they are totally innocent and the worst thing they did was pay a lot of money to hire a brilliant guy away from a competitor without realizing that he was downloading all this information?”